Basically, JKR has more or less admitted that Remus/Tonks wasn't in the original HP serie, but added after.
Before you think I'm crazy and delusional, let's go step by step.
1. Arthur was supposed to be killed in OotP. He's the character that got the infamous 'reprieve'. JKR has told us such in THIS interview.
2. Hence the need to 'exchange' him, kill off another father. Stated as such in the same interview.
3. She then admitted that the 2 deaths that weren't originally planned were those of Tonks and LUPIN! In THIS interview.
And who's the father who got killed off?
Without a death scene and in a really rushed way, I might add...
There you have it.
I can finally make my peace with HBP and how poorly the Remus/Tonks romance was set up and written. She added it in later, didn't develop it because it wasn't planned.
So people who said that the HBP/DH Remus wasn't the PoA/OotP Remus? (raise hand)